Our longterm overall goal is to collect both baseline data and repeated measures characterizing sleep disordered breathing, focusing on both respiratory events and arousal as independent variables in determining cardiovascular risk. The present proposal addresses collecting the baseline data, with the expectation that renewal of this project would allow the follow-up to be obtained. Our primary aim for this project is to collect data allowing the testing of several hypotheses about the relationship of SRBD and CV risk, including the development of hypertension and LV hypertrophy. Secondarily, we will test the hypothesis that sleep disruption and arousal will be a better marker of the severity of sleep related breathing disorders and therefore better predictors of cardiovascular morbidity than parameters derived from current respiratory monitoring techniques. Finally, we propose to examine and validate the ability of history and actigraphy to substitute for full polysomnography as the independent variables in analyses of risk for cardiovascular outcomes and in sequential testing of patient groups defined in the initial cohort. Validation of this approach would greatly facilitate future longitudinal studies which should evolve from the present data base.